ATI
Q46D-ODO Optical D.O. System
Part 6 - Calibration
52
O&M Manual
Rev-J (8/17)
2. Place about an inch of zero solution in a small beaker or other
convenient container and immerse the tip of the sensor. Allow the
sensor to sit undisturbed for at least 15 minutes. Suspend sensor, DO
NOT LET SENSOR SIT ON TIP.
3. Scroll to the CAL menu section using the MENU key and press ENTER
or the UP arrow key.
Cal D.O.
will then be displayed.
4. Press the ENTER key. The screen will display a flashing
1-spl
for 1-
point, a
2-%sat
for Saturation air calibration, or a
3-zer
for zero
calibration. Using the UP arrow key, set for a
3-Zer
zero calibration
and press ENTER.
5. The system now begins acquiring data for the sensor zero calibration
value. As data is gathered, the units for sensor millivolts (mV) and
temperature may flash. Flashing units indicate that this parameter is
unstable. The calibration data point acquisition will stop only when the
data remains stable for a pre-determined amount of time. This can be
overridden by pressing ENTER.
6. If the data remains unstable for 10 minutes, the calibration will fail and
the message
Cal
Unstable
will be displayed.
7. If accepted, the screen will display the message
PASS
with the new
sensor zero reading (offset), then it will return to the main
measurement display. If the calibration fails, a message indicating the
cause of the failure will be displayed and the FAIL icon will be turned
on. The range of acceptable value for sensor offset is -40 mV to +40
mV. Review the Service section of this manual, and then contact the
service dept. at ATI for further assistance.
The sensor offset value in mV from the last zero calibration is displayed on
the lower line of the Default Menus for information purposes.
6.2
Temperature Calibration
The temperature calibration sequence is essentially a 1-point offset
calibration that allows adjustments of approximately ± 5°C. If sensor cable
lengths beyond the standard cable length are being used the resistance of
this added cable will affect the temperature accuracy and will have to be
off-set to compensate for this added resistance.
